I. Field of the Invention
This invention relates generally to a conveyor system for use in a carton forming and sealing machine, and more particularly to a conveyor module capable of rotating the carton by 90xc2x0 while translating it from a first sealing station to a second sealing station.
II. Discussion of the Prior Art
In a carton forming and sealing machine, a flat blank of cardboard or paper board is first driven by a ram through a die to create a rectangular box configuration, the box having a bottom surface integrally joined to opposed side walls and end walls and a lid that is hinged along a top edge of one of the side walls.
These partially finished cartons may then have the product to be packaged placed therein and, subsequently, the box may be sealed in a two-stage gluing operation. At a first, upstream gluing station, a first tab comprising a folded extension of the lid beyond a mating side wall is adhesively bonded to that side wall. At a second, downstream gluing station, second and third tabs comprising extensions of the two side edges of the lid beyond the mating end walls of the box are adhesively bonded to the end walls of the box.
In fabricating the carton, a first overhead endless chain sweep conveyor or a conveyor having suitably spaced lugs on a conveyor chain may be used to translate the partially completed carton with the product therein past a hot glue gun at the first gluing station where a bead of glue is applied to the side wall surface to which the first extension tab of the lid is to be affixed. The sweep conveyor then urges the carton past a plow member which forces the first tab on the lid against the glue surface for a length of time sufficient to cause the glue to harden.
Before the second and third tabs comprising the extension of the two side edges of the lid can be glued to the mating end walls of the carton, the carton must first be rotated 90xc2x0 so that the end walls will then be oriented parallel to the direction of travel of the conveyor, allowing a pair of glue guns to apply beads of glue to the opposites end walls as they move past the glue guns. Again, plow members downstream of the glue guns are used to urge the second and third extension tabs against their respective end walls of the box as the carton is carried forward by a downstream sweep conveyor.
It is the principal object of the present invention to provide an improved conveyor module capable of receiving a partially sealed carton from an upstream gluing station and for transporting the carton to a downstream gluing station while simultaneously rotating the carton by 90xc2x0.
The conveyor module constructed in accordance with the present invention is operative to rotate products while in transit there along. The conveyor module comprises a frame having first and second sprocket wheels journaled for rotation on the frame about first and second, horizontal, parallel, spaced-apart axes, respectively. An endless chain spans the first and second sprocket wheels to define upper and lower chain flights. A generally rectangular carton support plate having upper and lower major surfaces is affixed to a first shaft at the center point of the lower major surface. The support plate further includes a cam follower on a second shaft that is affixed to the lower major surface and which is laterally offset from the first shaft along a midline of the rectangular support plate to the endless chain. The first shaft is secured by a coupler member so as to permit the support plate and first shaft to rotate about a longitudinal axis of the first shaft. The frame also supports a cam track where the cam track includes a first segment that is parallel to the upper chain flight over a first predetermined distance and which converges toward and intersects with the upper chain flight in a direction of travel of the upper chain flight. The aforementioned cam follower is adapted to engage the cam track to impart rotation of the support plate with the first shaft as the cam follower traverses the cam track.
An additional cam track is supported on the frame and it includes a first segment that diverges away from the lower chain flight at a predetermined angle and is joined to a second segment that extends parallel to the lower chain flight in the direction of travel of the lower chain flight. Means are disposed adjacent the first segment of the additional cam track for causing the cam follower to traverse the first segment of the additional cam track to cause a return rotation of the support plate.
To aid in holding the carton being fabricated to the support plate during its transport and rotation by the conveyor module, it may prove expedient to utilize a vacuum source that is pneumatically coupled to the support plate on which the partially fabricated carton is carried. To this end, the first shaft may be tubular and the support plate may include a cavity in fluid communication with the lumen of the tubular shaft. By providing an apertured pattern in the support plate and by operatively coupling the vacuum source to the lower end of the tubular shaft as it traverse the conveyor module, the carton is sucked against the upper major surface of the support plate.